#include "stdio_impl.h"
#include <string.h>

#define MIN(a,b) ((a)<(b) ? (a) : (b))

char *fgets(char *restrict s, int n, FILE *restrict f)
{
    char *p = s;
    unsigned char *z;
    size_t k;
    int c;

    FLOCK(f);

    if (n--<=1) {
        f->mode |= f->mode-1;
        FUNLOCK(f);
        if (n) return 0;
        *s = 0;
        return s;
    }

    while (n) {
        if (f->rpos != f->rend) {
            z = memchr(f->rpos, '\n', f->rend - f->rpos);
            k = z ? z - f->rpos + 1 : f->rend - f->rpos;
            k = MIN(k, n);
            memcpy(p, f->rpos, k);
            f->rpos += k;
            p += k;
            n -= k;
            if (z || !n) break;
        }
        if ((c = getc_unlocked(f)) < 0) {
            if (p==s || !feof(f)) s = 0;
            break;
        }
        n--;
        if ((*p++ = c) == '\n') break;
    }
    if (s) *p = 0;

    FUNLOCK(f);

    return s;
}

weak_alias(fgets, fgets_unlocked);
